Explanation:
The given data for case (1) is as follows.
h = 20 cm = 0.2 m
Assuming that a rectangular slab is placed above the pipe and we will calculate the heat transfer as follows.
Q = 
where, A = area
L = length
k = thermal conductivity = 0.8 W/m
= change in temperature.
Therefore, putting the given values into the above formula as follows.
Q =
= 
= 168 W
For case (2), h = 180 cm = 1.8 m
Therefore, heat lost will be calculated as follows.
Q =
= 
= 18.67 W
Thus, we can conclude that 18.67 W heat lost if the pipe was buried at a depth of 180 cm.
Answer:
E) All of the above.
Explanation:
Hello,
Since the acidic nature of the HCl implies its corrosiveness, when it is in contact with the skin and eyes the burning starts immediately, so gloves and goggles must be worn. Next, the fuming hydrochloric acid (37% by mass) is volatile so it gives off even when dissolved into water, so it must be used in the fume hood. Then, since vapors are produced during the chemical reaction, an overpressure could be attained, that's why we must keep the glass sash of the fume hood between us and the vial. As a common risk, the vial could be dropped causing the hydrochloric acid to splash, so we must keep the vial well inside the hood.
Best regards.
ANSWER:
4 a) Specific elements have more than one oxidation state, demonstrating variable valency.
For example, the following transition metals demonstrate varied valence states: 
, 
, 
, etc.
Normal metals such as 
also show variable valencies. Certain non-metals are also found to show more than one valence state 
4 b) Isotopes are members of a family of an element that all have the same number of protons but different numbers of neutrons.
For example, Carbon-14 is a naturally occurring radioactive isotope of carbon, having six protons and eight neutrons in the nucleus. However, C-14 does not last forever and there will come a time when it loses its extra neutrons and becomes Carbon-12.
5 a) 
→ 
5 b) 
→ 
5 c) 
→ 
(already balanced so don't need to change)
5 d) 
→ 
5 e) 
→ 
EXPLANATION (IF NEEDED):
1. Write out how many atoms of each element is on the left (reactant side) and right (product side) of the arrow.
2. Start multiplying each side accordingly to try to get atoms of the elements on both sides equal.
EXAMPLE OF BALANCING:
<span>The
kingdom, protista’s characteristics are that the organism (not a plant,
animal or fungus) are:
unicellular however some are multicellular like algae, are heterotrophic or
autotrophic, others lives in water while some live in moist areas or human body,
have a nucleus, cellular respiration is primarily aerobic, some are pathogenic
(e.g. causing Malaria) and reproduction is mitosis or meiosis. This kingdom
includes: Sacordinians – pseudopods (e.g. Amoeba, Foraminiferans<span>.)</span>, Zooflagellates – flagellates
(e.g. Trypanosoma gambiense),
Ciliaphorans – ciliates (e.g. paramecium) and Sporozoans (e.g. Plasmodium).</span>
The peripheral nervous system<span>, or </span>PNS<span>, consists of the nerves and ganglia outside of the brain and the spinal cord. The main </span>function of the PNS<span> is to connect the central </span>nervous system<span> (</span>CNS<span>) to the limbs and organs.</span>
